1. Field of the Invention
This invention relates in general to storage boxes and in particular to seed boxes adapted for vertical stacking.
2. Description of the Prior Art
In the manufacture of seed boxes, which may hold from 2,000-4,000 pounds of seed each, it is highly desirable to make the boxes as light and the least costly as possible, and yet make them strong enough that vertical stacking of five or six loaded boxes will not cause the lower boxes to collapse.
Heretofore, seed boxes have been of two general types, both constructed of sheet steel. The first type, as typified by U.S. Pat. No. 2,664,219, issued to T. Schmidt, includes four vertical walls, folded corners, and stacking flanges top and bottom for placement of one box upon another. Such boxes also typically include stacking pins or handles so that one box does not fall within another. The requirement of stacking flanges, top and bottom, add to the weight and cost of the boxes and generally require greater storage space per unit volume because of the overhang of the flanges.
The second type of box currently in use, storing the most seed in the least space, are boxes having walls tapered from bottom to top; the top usually being about 3 inches less in width than the bottom. A stacking flange is then placed about the top periphery only of the box for stacking purposes. All known boxes of this tapered sided type include corner welds. The sides are simply cut to the desired tapered dimensions and then welded together at the corners. The primary problem with this tapered sided type of box is that typically the welds on the corners split with age, use, fatigue and crystallization, and then the box fails, which may result in an entire stack of boxes falling over. This is costly, as it ruins certified seed and split boxes may be dangerous to forklift operations.
Other patents of relevance are those of S. Dezawa, U.S. Pat. No. 4,381,842, showing a metal enclosure having four walls formed by folding a single plate; and B. D. Jones et al, U.S. Pat. No. 3,318,473 showing a dispensing bin.